Azimuth-chronometer.



H. S. BUTTERFIELD.

AZIMUTH CHRONOMETER.

APPUCATION FILED MAR. 30. 1912.

Patented Mar. 13, 1917.

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H. S. BUTTERHELD.

AZlMUTH CHRONOMETER.

APPLICATION FILED MAR, 30, 1912.

l ,291 9, Patented Mar. 13, 1917.

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H. S. BUTTERFIELD- AZIMUTH CHRONOMETER.

APPUCATION FILED MAR. 30] i912- 1,21 9,37%. Patented Mar. 13, 1917.

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1/ u u M H. S. BUTTERFIELD. AZIMUTH CHRONOMETER.

APPLICATION FILED MAR. 30. 1912.

1,21 9,372. Patented Mar. 13, 191?.

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W- @WMQ HORACE S. BUTTERFIELD, OF PORTLAND, OREGON.

AZIMUTH-CI-IRONOMETER.

Specification of Letters Patent.

Patented Mar. 13, 1%17.

Application filed March 30, 1912. Serial No. 687,325.

To all wlwmz't may concern:

Be it known that i, HORACE S. BUTTER- FIELD, a citizen of the UnitedStates, and resident of Portland, in the county of Multnomah and Stateof Oregon, have invented certain new and useful Improvements inrizimuth-Chronometers, of which the following is a specification.

The object of the present invention is to provide an instrument ofprecision, adapted, among other things, to designate the true bearing ofthe sun or any other celestial body continuously through successivepoints of time, and including an automatic driving motor and mechanicalconnections by which a sighting means may be moved in a mannerconforming to the alteration in the true bearing, or azimuth, of thecelestial body. Another object which is related to the foregoing objectis to provide a novel and improved mechanism by which a telescope may beso moved as to maintain its line of sight upon a celestial bodythroughout the apparent movement of the body with relation to the earth.It is my purpose to provide means by which the sighting member may bemoved in a horizontal plane at the same rate as the change in thebearing of the sun or other distant object with which the sightingmember is alined, to the end that compass errors and true directions maybe accurately determined continuously during successive points of time.

Reducing the invention to a practical embodiment of means, I havedevised a mechanism by which a driving member traveling at a uniformrate of speed is enabled to produce variable movement in a drivenmember, and provisions for so adjusting the driving member that thevariation in the movement of the driven member may also be varied fromnothing (in which case the driven member has uniform motion) to theopposite limit where no motion whatever is giren to the driven member,which I believe to be broadly novel, and for which I desire protection.The instrument which I hare produced in reducing my invention topractical form, and which is one of the possible constructions in whichthe essential principles of the invention may be embodied is illustratedin the accompanying drawings and described in the followingspecification.

In the drawings,

Figure 1 represents a vertical transverse section of the lnstrument.

Fig." 2 is a vertical section at right angles to that of Fig. 1.

Fig. 3 is a plan View of the instrument.

Figs. f and 5 are detail elevations of the driving mechanisms, showingthem in different adjustments.

Fig. 6 is a sectional view illustrating a detail of the construction.

Fig. 7 is a detail elevation of a portion of the mechanism.

Figs. 8 and 9 are, respectively, a sectional view and elevationillustrating the application. of the principles of the invention to anastronomical telescope and the additional means for controlling theelevation of the telescope.

I will first describe the construction of the instrument and theprinciples involved therein, and will then explain some of the purposesand uses for which it is designed and to which it may be applied.

The particular instrument here shown includes a case or boX 1 in which aring 2 is hung by means of diametrically opposite pivots or trunnions 3,Within the ring 2 is a second ring 5 hung by diametrically oppositepivots 6, 7 on an axis at right angles to the axis of the first namedpivots. A weight 8 is suspended from the ring 5 by a suspension means 9by which the ring is enabled to remain horizontal by turning about thegimbal pivots, however the boX or case may be inclined.

The inner ring carries bearing blocks or chairs 10 on which is supporteda pelorus or dial 11, the latter being sufficiently free to enable it tobe rotated in a horizontal plane. Secured to the under side of thepelorus and depending therefrom in a diametral plane is a rigid andsufiiciently strong and massive bar or bow 12 which is circularlycurved, through an arc of preferably more than one hundred and eightydegrees. This how serves to support and provide for adjustment of thedrivingmechanism of the instrument.

Resting upon an inner face 13 of the bow is a complementally curvedplate 14 having ears 15 which embrace the bow, as best shown in Fig. 1,and divergent arms 16 to and between which is secured a motor 17 Thismotor may be of any desired character provided only it is capable ofrunning at a substantially uniform rate of speed. Preferably it is aspring driven watch or clock having all the usual parts of such a timepiece, including a dial and hands. Conveniently the dial and hands areon the side of the clock to which the numeral 18 is applied, althoughthe position of these parts is immaterial, provided they are so placedthat they can be seen. A head 19 is provided for winding and setting theclock by means of any of the mechanisms commonly used for this purpose.The clock is not illustrated more in detail because the one used in thepresent instrument is a standard eight-day clock of well knowncharacter, and in itself is not a part of the invention. It is merelyone type of driving motor, and in one of the aspects of the invention isto be considered as simply an embodiment of means for producing motionat a uniform rate of speed. The plate 14: and lugs 15 fit accuratelyupon three sides of the curved bar 12. Bearing on the fourth or outerside are springs 20 which are confined between such fourth side and apinion shaft 21 which is journaled in the lugs 15 and extends across thespace between the latter. There are two springs 20 which are separatedand flank a circular line of teeth 22 on the outer face of the bar 12,and a pinion 23 is mounted upon the shaft 21 between the springs andmeshes with such teeth. Rotation of the pinion 23 by means of a head 2%on the shaft 21 causes the parts which are engaged with the bar 12 to bemoved in one direction or the other along the latter, and causes theclock or motor, which is locatedapproximately at the center of curvaturein the bar 12 to be moved angularly about such center.

Pivoted at one side of the clock or motor 17 by means of a shaft 25which has a sufficiently firm bearing in the frame of the motor, is aframe 26 which carries a circular ring 27 toothed on one edge at 28 andsurrounding the motor 17. The toothed edge of the ring 27 forms acircular curve which is in a plane passing close to the center ofcurvature of the bar 12 and of which the center of curvature lies in theline of the pivotal axis 25, which is also the geometrical axis of thering 27. A pinion 29 is mounted on a staff 30 which forms a continuationof one of the shafts or staffs of the motor 17, and meshes with theteeth 28 of the ring 27 When, as in the present case, the motor is aclock movement, the staff 30 is a continuation of, or is driven by, thecenter staff of the movement, which makes a complete rotation everyhour. The gear ratio between the pinion 29 and ring 27 is such that thelatter rotates once in every twentyfour hours. In any event, Whatevermay be the type of motor used,'the speed is so regulated as to cause thering 27, or

its equivalent, to have this rate of rotation,

and to maintain the rate uniform at all times. Mounted upon the ring 27at diametricall o3 )osite oints thereof are studs 31 and 32, of whichthe manner of mounting is sufficiently shown in the drawings. 7

form a function in producing a variable motion which I will now describein connection with a sighting member or device.

In the center of the pelorus or dial 11 is a stud 3i which rotateswithin the dial on a vertical axis and is supported upon a frictionlessball bearing 33, as shown in Fig. 1. Secured to this stud is an arm orframe 34: which carries vanes 35 and 36 pivoted upon horizontal pivotsat diametrically opposite sides of the stud 32. Sue of the vanes, as 35,carries a slide 37 having an aperture 38, across which extends a screen39 for diminishing the intensity of the suns rays. The other vane isopen and carries a fine wire 40 which is arranged in a vertical plane.Pivoted to the outer side of the vane 36 is a mirror 41. The mirror andsighting vanes co-act with one another for finding the bearing of thesun, or a star, or any other distant object. I do not restrict myinvention to sighting members of this particular character, or indeedeven to any sighting means whatever, properly so called, for anysighting means is one form of indicator by which angles or directionswith respect to a specific point on the dial nay be shown, and anyindicator of whatever character comes within the scope of my invention.when employed in connection with the dial in essentially the mannerhereinafter described.

Secured to the stud 32 beneath the dial is a member which I term a yokeor' guide. It comprises arms 42,43 which embrace the ring 27 and ofwhich each is a continuation of the other.- These arms are circularlycurved and contain a correspondingly curved uninterrupted guideway 4A-which is in an axial plane of the stud 32 and of which the center ofcurvature is the points at which the axis of curvature of the bar 12intersects the axis about which the ring 27 and studs 31 and 32 rotate.The width of the guideway 44 is such that the studs 31 and 32 have aclose sliding fit therein.

From the foregoing description the mechanical operation of theinstrument may be understood. Assuming first that the adjustment is asshown in Fig.2, then the path in which the studs 31 and 32 travel isinclined both to the axis of the yoke or guide and to the path in whichany point of the yoke or guide rotates. lonsequently, assuming therotation of the ring 27 to be in the direction of the arrow appliedthereon in Fig. 2, the stud 31 in traveling up the incline enters theguide way in the end of the yoke arm 42, and imparts motion thereto. Thefirst part of this motion is relatively slow on account of the obliquityof the movement of the stud to the yoke arm, but as the yoke arm, inswinging, becomes more nearly perpendicular to this path of motion, andas the stud travels up in the guide way nearer to the axis of thelatter, the speed of the yoke accelerates until it passes the point atwhich its plane coincides with a plane including the stud and the axisabout which the stud rotates, when the speed of that. point of the yokewhich is engaged by the stud is equal to the speed of the stud.Thereafter, the speed of the yoke begins to diminish. Continuing untilthe yoke has turned through a half revolution, (the position shown inFig. 2) the stud 31 passes out of the guideway at the end of arm 42, butjust before the stud 31 issues from the guideway, the stud 32 enters thearm 43, be-

cause these arms extend through at least one hundred and eighty degreesof are, as shown in Fig. 1. Thereupon the rotation of the yoke iscontinued and completed with the same accelerated and retarded motion bythe stud 32 acting'on the arm 43. An exactly similar motion ofhorizontal rotation is imparted to the sight vanes, and corresponds tothe change in the bearing of the sun at the equinox in the latitude forwhich the instrument is set, because the studs travel in an orbitparallel to the apparent orbit of the sun with respect to the earth.

Other variable rates of movement between uniform motion and no motion atall are imparted to the yoke and sighting member according to theinclination of the path of movement of the studs. One extreme adjustmentis illustrated in Fig. 4, where the slide is carr ed so far along thebow 12 that the path in which the studs move is horizontal, that is,parallel to the dial and perpendicular to the axis of the yoke. Thus theyoke is rotated at a uniform rate of speed, which is the same as therate of speed of the studs. The other extreme adjustment is shown inFig. 5 where the path of the studs is vertical, being perpendicular tothe dial 11 and in a plane which includes the axis of the yoke. The yokethen assumes a position coinciding with. the path of the studs andisgiven no rotation whatever.

The bar 12 is graduated in angular degrees, running in both directionsfrom a Zero indication at 45. The plate or slide 14 carries an indexmark 46 and graduations on each side thereof so placed as to form aVernier. The graduations are so positioned on the curved bar that, withthe adjustment shown in Fig. 4, the index 46 is on the ninety degreemark, which corresponds to the latitude of the North Pole. Then theuniform movement given to the sighting members corresponds to theuniform change of the bearing of the sun at the pole. lVith theadjustment in Fig. 5 the index is on Zero, corresponding to the latitudeof the equator, and the absence of movement corresponds to theconditionin this latitude at the equinoxes, when the sun passes directlyoverhead without changing its bearing except at noon, when it shiftsfrom east to west. In this position of the instrument, as previouslydescribed no motion is given to the sighting members. In other settingsof the mecha nism the movement of the studs 31 and 32 corresponds to theapparent movement of the sun in latitudes corresponding to the degreesof the scale at the time of the equinoxes. Consequently the variablemotion imparted by the studs to the sighting members corresponds to thetravel of the suns projection on a horizontal plane, and thuscorresponds to the momentary changes in the suns bearing.

Une of the uses of the instrument is to determine the true bearing, orazimuth, of the sun, in order to show compass errors. In explaining thisuse, I will assume first that it is made at the time of either equinoxbecause at these times the sun follows the equatorial plane of theearth, and the use of the instrument is most simplified. Then the index46 is set on the latitude of the place where the observer is located,and the hands of the clock set at local time. This setting of the handscauses the mechanism to be operated in the manner already described sothat the sighting members occupy positions corresponding. to the time ofday. Then the instrument is placed in the sun and the pelorus is shifteduntil the sighting members are in line with the sun. The compass pointson the pelorus then indicate the true directions. The instrument can bethus used at any time of day and without reference to azimuth tables,because the motor automatically takes care of the change of hearing atdifferent points of time.

At other times than the equinoxes the suns declination is a factor to beconsidered and is taken care of in the setting of the index 46, byadding or subtracting the declination to or from the latitude, accordingto the season. For illustration of the last statement let it be assumedthat the place at which the instrument is used is latitude forty-fivedegrees north and the sun is at the summer solstice. The declination ofthe sun is then twenty-three and one-half degrees north (approximately).To determine the setting of the index, twenty-three and one-half issubtracted from forty-five and the index as is then set on thegraduation indicating twenty-one and one-half degrees at the left of thezero mark45. At the winter solstice, when the declination of the sun isabout twenty-three and one-half degrees south, the amount of thedeclination is added to the latitude in order to determine the settingof the instrument, and the index -16 is consequently placed beside themark indicating sixty-eight and one-half degrees. At other times of theyear the instrument is otherwise set according to the suns declinationfor the particular day on which the instrument is used, which may bereadily found from astronomical tables. When the sighting members arethen alined with the sun the bearing is given with approximatecorrectness at all times within a few hours before and after noon,because, during the middle part of the day the apparent motion of thesun at the place of observation corresponds very closely to suchapparent motion at the times of the equinoxes in latitudes twenty-oneand one-half degrees north, sixty-eight and one-half degrees north orother latitudes which correspond to the degrees of latitude of the placeof observation'increased or diminished by the declination of the sun onthe day of observation.

A difference in the mode of use of the in strument is made according asthe observer is in the Northern or Southern Hemisphere. When in theNorthern Hemisphere the setting for latitude is made at the left of thezero indication and when in the Southern Hemisphere it is at the rightof zero (with respect to the position of the instrument as seen in Fig.2.) Thus in the Northern Hemisphere the rotation of the sighting membersis clock-wise and in the Southern Hemisphere is anti-clockwise, andcorresponds with the course of the sun. The statement above made is trueas to observations made outside of the tropics at all seasons of theyear, but in the tropics the action is modified by the setting for thesuns declination, the direction of rotation being clockwise oranti-clockwise according as the sun is respectively south or north ofthe place of observation.

In a similar way the azimuths of stars may be taken, the declination'ofthe star and the local mean time of the star being known, and theforegoing explanation made with reference to the sun applies exactly toobservations taken upon any fixed star.

Owing to the necessity of providing a support for the transmissionmechanism outside of the pivotal axis about which the mechanism isadjusted, in order that the studs 31 and 32 may rotate withoutinterference with the support, the extent to which the adjustment may bemade to the right relatively to -Figs. 2, 4, and 5 is limited. That is,the adjustment can not be made beyond the point at which the yoke arms12, 43 interfere with the supporting arms 16. Consequently although theinstrument as here shown is degrees south, I provide an alternativemeans for producing reverse rotation of the annular gear 28, whichaccomplishes the same effect as swinging the adjustment from the left tothe right of the Zero indication of the scale. This means consists of apinion 50 mounted on a staff or shaft 51 which is in alinement with thestaff 30 and engages the annular gear 28 at a point diametricallyopposite to that of the pinion 29. Each of the staffs 30 and 51 isdisconnectibly engaged with the center staff or shaft of the time piece,whereby either one may be connected and the other released. Convenientmeans for this purpose consists of clutches or binders 52, 53.

From the preceding description of the construction and mode of use ofthe instrument, it will be readily seen that the setting of the slide 14as previously described with its index beside the graduation on thecurved bar 12 which corresponds to the latitude of the place ofobservation, so inclines the annular gear 28 that the studs 31 and 32carried by said gear travel in a plane parallel to the earths equatorialplane, which is also the plane in which the apparent motion of the sunoccurs at the equinoxes. Similarly the setting of the adjustable annulargear to take into account the declination of the sun or other celestialbody of which the azimuth is to be taken, in the manner described causesthe path of the studs to be displaced from such plane at an angle whichis equal to the angle of declination of the sun or other celestial bodywhen near the meridian, and therefore causes the studs to follow theapparent movement ofthe sun or other celestial body when such body iscross ing the meridian and is within thirty or forty-five degrees of themeridian at either side. When the instrument is used in latitudes southof the equator and the direction of rotation of the annular gear isreversed by putting the pinion 50 instead of the pinion 39 into drivingconnection with the motor, and the settings of the index 46 are made asthough for use in northern latitudes, then the studs 31 and 32 arecaused to travel in a path perpendicular either to the earths equatorialplane or to the plane of apparent movement of the celestial body, but asthe direction of rotation of these studs is reversed, the same effect issecured through the transmission mechanism as though the settings wereat the right of the index mark CAD (with respect to the positions of theinstrument indicated in the drawings).

If the principles of the transmission mechanism are analyzed, it will beseen that they comprise essentially a driving member, (either the stud31 or the stud 32), a driven element (the yoke 42, 43), and a guideelement (the groove 4%), which is a part of the driven member and isengaged by the driver. It will be further seen that the axes of rotationof these members or elements cross each other and are inclined more orless to one another in all except the two extreme adjustments. In one ofthese extreme adjust- 1 ments such axes coincide, and in the other theyare at right angles to each other. The adjustment of the driving memberto secure variations in the character of variable movement of the drivenmember occur about the point of intersection of the two axes in such adirection that the axis of rotation of the driving member is shifted inthe plane of the axes angularly about the point of intersection to widenor contract the angles be tween the axes.

It is essential, in order that the engagement between the driving anddriven members should be maintained in all adjustments and at all pointsin the path of the driving member, that the guiding element, or thatportion of the driven member which is engaged by the driver, should becurved in spherical relation to this point of intersection, or in otherwords, that it should lie in the surface of an imaginary sphere of whichthe center is the said point of intersection. As here shown the guidingelement is in a great circle of such imaginary sphere and includes theaxis of the driven member, although this particular condition may not beessential in every embodiment and aspect of the invention. The essentialcondition is that the guiding element should be continuous andequi-distant at all points from the center described.

The face of the dial 11 is inscribed with marks by which bearings may beindicated. Preferably its periphery is graduated in angular degrees, andin addition the dial may be inscribed with the points of the compass. Ihave provided in addition to the mechanism already described a means bywhich fractional parts of the divisions of the graduations may be read.This means comprises a subsidiary dial 54L- on the dial 11 andpreferably graduated in degrees and fractions thereof, and a hand orpointer 55 which is driven synchronously with the motion of the sightingmember. The driving means comprises a gear 56 secured upon the part 8and a pinion 57 in mesh with the gear and secured to the staff 58 whichcarries the hand 55. The gear ratio is such tnat the movement of thehand 55 is considerably more rapid than the movement of the frame 34.

T he same or equivalent mechanism maybe applied to an instrumentdesigned to followthe path of a celestial body when coupled with meansfor adjusting elevation of the sighting instrument. invention adaptedfor this purpose is shown in Figs. 8 and 9 where (30 represents anastronomical telescope having iorizontal alined pivots 61 journaled in afran e 62 mounted to turn about a vertical axis on a bearing 33. Thetransmission mechanism is substan tially identical with that alreadydescribed and the parts thereof are identified by similar referencecharacters. There is a modiication in the character of the drivingmotor, in that the motor is detached from the instrument itself andmovement is transmit ted from the motor by a shaft 63 which isfiexil'ily connected in any suitable or known manner with the shaft 30and pinion 29. This mechanism produces a horizontal. rotation of thetelescope, that is, rotation about a vertical axis, in exactly themanner described. The angle of elevation of the telescope is controlledby a traveler G l which is arranger. to slide in a guide way in one ofthe arms of the upright frame (32 and has a pin or stud 65 entering acam groove 66 in a wheel 67 pivoted at 68 to the upright frame. Thiswheel is toothed and meshes with a complemental toothed vwieel 69 on oneof the pivots (31 of the telescope. A flexible pusher extends from thedriver (i-l into the guideway of one of the yoke arms 4-3 and is adaptedto be engaged by either of the driving studs 31 or 82 entering theguideway. This pusner is preferably a line of balls '1" 0 and is therebyadapted to follow a sinuous course without elongation or contraction.Assuming that the telescope is so poised or weighted as to tend to swinginto the horizontal position. its weight maintains a downward pressureupon the driver 6% and pusher 70, requiring only compressive force to beexerted on the latter and taking up all backlash. The cam (36 is sodesigned that equal movements of the driver produces equal amounts ofangular rotation of the wheels 67 and 69. Hence movements of the stud 31in the path of the celestial body under observation producecorresponding morements of the telescope and keep the latter trainedcontinuously upon the body. A stop 1 is mounted at the lower end of theguide way a l and is of suitable form and dimensions to allow the stud31 to pass it and to prevent the balls from falling out of the guideway.

7 The instrument made as above described or made in any other ormodified manner, or in any manner, provided it includes the essentialprinciples of my invention herein before explained, is capable of wideand varied uses in navigation, surveying, astronomical work, etc. Ttwill be understood that A modification of the 1 factors in the use ofthe instrument are, lati tude, local mean time, declination of the sunor stars, azimuths and the true meridian. With one or more of thesefactors known, the others may be determined by proper use of theinstrument. Not only can it be used to determine the true bearing of thesun or a star and thus establish the meridian and determine compasserrors, but it may also be used as a means for determining latitude andlongitude. It may also be employed as a compass in parts of the earth.where magnetic variations render the magnetic compass unreliable. Thisinstrument in combination with a means for showing the time at a certainknown point on the earths surface can be used for all the purposes ofnavigation without the aid of any other instrument or tables. Inaddition, I desire to apply the invention to a means for setting timepieces by the sun, to serve the purpose of a sun dial or sun-timeindicator in open places, and to serve as a means by which local meantime or local sidereal time may be accurately and immediatelydetermined.

I am aware that the essential principles of the invention heretoforeexplained may be embodied in forms and modifications differing in manyways in external appearance from the particular construction illustratedand described in this specification. All such modifications are withinthe scope of myinvention provided they contain the elements, or theirequivalents, of the appended claims.

So far as I am aware the mechanism according to which the variablemovement of the sighting vanes or driven member is de rived from uniformrotation of the driver, is a new idea of means for transmitting motion,and as such is capable of a wide variety of uses in driving mechanicalparts which are designed to have variable speeds. I declare, therefore,that I do not limit my invention, in respect to the driving mechanism,

-- to the combination with the sighting or indicating means of anazimuth instrument, but that I include within the scope of my inventionand of certain of the following claims, mechanism designed for anypurpose whatever in which the axes of the driver and the driven memberare adjustableat various angles, and in which the transmittingconnection between these members includes.

a guide occupying a spherical relation to a common point in said axes.

curved concentrically about the common point of the said axes on whichsaid driver is adjustably mounted, and transmission means between saiddriver and driven member including a guide curved about said commonpoint and a sliding element occupying said guide, said support beingextended through an arc of at least ninety degrees and positioned topermit the driver to be adjusted with its axis perpendicular to the axisof the driven member or in coincidence therewith, or at any intermediateangle with respect thereto.

2. The combination of a driver and a driven member arranged to rotaterespectively about axes which pass through a common point, a supportcurved about said common point in a plane other than perpendicular tothe axis of the driven member, the driver being mounted on said supportwith provision for adjustment thereon about said common point, and thesupport extending through an arc of at least ninety degrees whereby saiddriver may be placed with its axis perpendicular to or in coincidencewith or at any intermediate angle to the axis of the driving member, andtransmission means for imparting movement from the driver to the drivenmember.

3. An apparatus comprising a driver and a driven member rotatablerespectively about axes which pass through a common point, motiontransmitting means between said members comprising a guide connectedwith the driven member and a slide connected with the driver andengageable with said guide, said guide'being continuous on an arc ofuniform radius of which the center is said common point and which passesthrough the axis of the driven member and extends approximately ninetydegrees on each side of such axis, and means for supporting the driverwith provision for adjustment angularly about said common point in aplane other than perpendicular to the axis of the driven member, betweenpositions of which it is respectively perpendicular to and incoincidence with the axis of the driven member.

4. In an apparatus of the character described, a driven member rotatableabout an axis, a yoke secured to said driven member and curved about apoint in such axis in a plane including the axis, said yoke having aguide portion crossing such axis and extending on an arc of uniformradius about such point approximately ninety degrees on each side of thesaid axis, a driver having a slide occupying said guide, and a supportadjustably holding said driver, the support being curved about the axisof said yoke at a plane including the axis of the driven member, and thedriver being supported with its axis in the same plane and passingthrough the same central point.

5. An apparatus of the cha 'acter described comprising driving anddriven members adapted to rotate about axes which pass through a commonpoint, a transmission member connected to the driven member and having acontinuous guideway of uniform radius curved about said common point ina plane passing through the axis of the driven member and extendingapproximately ninety degrees each side of said axis, said driving memberhaving an ele ment occupying said guideway, and a support curved on anare about the same common point in a plane passing through said axis andhaving a radius greater than that of said t ansmission member, andextending through an arc of at least ninety degrees, and meansconnecting said driver to said support arranged to hold the driver Withits axis radial to such common point and in a manner permitting suchaxis to be brought perpendicular to the axis of the driven memberWithout interference therewith.

6. An apparatus comprising a driver and axis of the driven member andcrossing saidxvithout interruption, the driving memher having an elementengaging said guide member, a. self-contained motor connected with saiddriver for operating the same and contained Wholly Within the spaceembraced by said transmission member, and a supoort lying Wholly outsideof the path of said transmission. member on which said driver isadjustably mounted.

T. An apparatus comprising a driver and a driven member adapted torotate about arcs passing through a common point, a transmission memberconnected with said driven member curved about said common point on anarc of uniform radius in a plane containing the axis of the drivenmember and crossing said axis "ithout interruption, the driving memherhaving an element engaging said guide member, a self-contained motorconnected with said driver for operating the same and contained whollyWithin the space embraced by said transmission member, and a su portlying Wholly outside of the path of said transmission member on Whichsaid driver is adjustably mounted, said support being curved about saidcommon point in a plane containing the axis of the driven member, andthe mounting for said driver being a slide arranged to travellongitudinally on said support and including a connecting arm leadingfrom said support and making an angle of more than ninety degrees Withthe axis of the driver.

D carried bv said driver, a

and having a guide portion h. fin azimuth instrument comprising a su'uio tino' means or standard, a dial, a gimbai join 1;}; upon saidstandard and upon which said dial is mounted with provision tor rotationin its own plane, a curved bar or boiv connected with said dial anddepending from the under side thereof, a sighting means rotatablymounted on said dial to turn about a vertical axis, said bow hafng aguiding portion curved about a point in s. cl1 axis and occupying aplane which passes through the is, a slide mounted upon said guideportion with provision for ustment longitudinally thereon, a drivingmember rotatably supported on said slide with its axis of rotationpassing through the center of said guide portion, means for rotatingsaid driver and motion t'ransn'iission connections between said driverand said sighting means.

9. An azimuth chronometer comprising a supporting means having abearing, a sighting member rotatably mounted in said bearing, a urvedbar depending from the under side of-said bearing and curved about apoint in the axis of the sighting means and occupying a plane whichpasses through said axis, a slide mounted on said curved bar withprovision for adjustment longitudinally thereon, a timepiece mountedupon said slide in a central position with respect to the cu ved bar, adriver rotatably mounted on the timepiece mounting with its axis passingthrough the center of curvature of the b: gearing through which saidtimepiece rota said d r driving element transmission memected to thesighting means and de portion engaged with said her con having a 1driving cle ue curved about the (eater of ;it, FRi(l guide portion beingthe curved bar on a bus less than l 3 radius of the bar and greater thanthe distance of any point of the timepiece or driver from said center,

said traiismissio member having a guide portion eng with said drivingelement.

18. An ruth clnronometer comprising a driver rotating at a imiform rate,a driven member mounted and arranged to rotate in a horizontal plane. acurved guide element connected with said driven member lying in a planewhich includes the axis of rotation Oi the driven member, and a travelercarried by said driver constructed to engagesaid guide element andtravel in contact therewith, the axis of rotation of said travelerpassing through the center of curvature of said guide element, and meansfor supporting said traveler located clear of the orbits of all pointsin said guide element.

11. Au azimuth chronometer comprising a horizontally rotatable memberand means for driving said member continuously throughout more than acomplete rotation at a rate corresponding to the rate of change rate ofspeed, said shaft being adjustable,

at an inclination corresponding to the latitude of the place of use, andmeans for continuously transmitting motion from said driving shaft tosaid driven member arranged to permit complete rotation Withoutinterference.

12. An azimuth chronometer comprising rotatable driving and drivenelements so adjustable that their axes may be relatively changed to anydesired angle about their point of intersection, aprime mover locatednear the point of intersection of such axes, and transmission means at agreater distance than the prime mover from said point rotatable aboutsuch prime mover and driven by the latter.

13. In an instrumentof the character described, a rotating driven memberhaving guide members extending equal distances to opposite sides of theaxis of rotation thereof and curved concentrically about a point in suchaxis, a driver comprising one or more elements adapted to travel in saidguide members and supported to rotate about the same point with whichsaid guide members are concentric, said driver being also adjustableabout the same point to various angles with respect to the axis of thedriven member, and a prime mover located within the space circumscribedby the travel of said guide members and driver.

14. An apparatus of the character inclicated comprising a pivotally hungand pendulum-weighted support, a meridian index mounted horizontallyupon said support and adjustable about a verticalaxis, a sighting meansrotatable horizontally about the same axis, a curved bar or bow hungfrom said support and occupying a plane which passes through said axis,a holder mounted upon said bow and adjustable along the same, a clocksupported by said holder within the space inclosed by the bow, anannular Wheel surrounding the clock and journaled thereon upon an axisperpendicular to the plane of the wheel, gearing driven by the clock fordriving said wheel at the angular rate of rotation of the earth, studssecured upon said wheel at diametrically opposite points thereof andarranged to travel in a plane of which the center coincides with theaxis of. curvature of said wheel and with the axis of rotation of saidsighting means, and a yoke curved concentrically with the same axis,carried by the sighting means, and having a guiding element inengagement with one or both of said studs.

15. An azimuth instrument comprising a graduated dial adapted to berotated in a horizontal plane, a support connected to said dial andcurved about a point in the axis of the dial, a driven member rotatableabout the axis of the dial, a driver mounted upon said support withinthe space embraced by the support and mounted to rotate about an axiscrossing the center of curvature thereof, and transmission mechanismcomprising a guide connected with the driven member and curvedconcentrically about said center, and a traveler carried by the driverand engaging said guide, the guide being located within the spacesubtended by the support, whereby it is enabled to rotate completelywithout interference with the support.

16. An azimuth instrument comprising a curved support, a holder mountedupon said support with provision for adjustment longitudinally thereofand extending toward the center of curvature thereof, a driver mountedupon said holder arranged to turn about an axis passing through thecenter of curvature of the support and making an angle With the holder,a traveler or slide carried by the driver at a distance from the axis ofrotation thereof, and a driven member mounted to rotate about an axisintersecting the axis of the driver in the center of curvature of thesupport and including a guideway curved about such pointof intersectionand at a less distance therefrom at all points than the support, saidguideway receiving the said traveler.

17. An azimuth instrument comprising a relatively fixed support curvedabout an interior point and constructed to leave an open space on itsconcave side, a holder mounted upon said support with provision for ad'justment along the same, having a portion extending toward the axis ofthe support, a motor carried by said holder, an annular gear surroundingsaid motor and mounted thereon to rotate about an axis crossing thecenter of curvature of the support, a pinion driven by the motor meshingwith said gear for rotating the latter, a traveler or driver carried bythe annular gear externally thereof, a driven member mounted to rotateabout 7 an axis intersecting the axis of the support, and a guideelement connected to the driven member curved concentrically about thepoint of intersection of such axes and engaged with said driver, saidguide element being situated intermediate the annular gear and theimaginary spherical surface of which the support is a meridian.

18. An azimuth instrument comprising a dial, sighting means mounted torotate about the axis of said dial, a yoke connected to said sightingmeans having a guide portion extending on opposite sides of said axisand equally distant at all points from a point in such axis, a supportsecured to said dial extending on a curve of uniform radius about'thesaid point as a center and being at a greater distance than the guideportion from said point, and a driver adjustably mounted upon saidsupport and arranged to rotate about an axis passing through said point,and engaging said guide portion.

19. An azimuth chronometer comprising a timepiece, a holder for saidtimepiece, a support for said holder, an annular gear mounted upon thetimepiece and surround ing the same, a pinion driven by the timepiecefor rotating said annular gear, a sighting means rotatable about avertical axis and transmission mechanism for rotating the sighting meanscomprising a stud carried by the said annular gear and a guide memberconnected with the sighting means adapted to receive said stud, saidguide and the support being curved about a common point which lies inthe axis of the sighting means, and the axis of rotation of the annulargear passing through such common point, the support being more distantat all points from such common point than any part of said guide member,and the holder for the timepiece being adjustable on the support,whereby the axis of the gear may be placed at a variety of angles withrespect to the axis of the sighting means.

20. The combination of a rotary driver, a rotary driven member having aguide portion, a holder for the driver and a support for said holder,the said guide portion and support being curved about the same point inthe axis of the driven member and the support being at a greaterdistance from said Copies of this patent may be obtained for point thanany part of the guide portion, whereby a complete rotation of the latteris permitted, and the driver being mounted to rotate about an axispassing through the same point and having a traveler arranged andconstructed to engage said guide portion and apply force thereto.

21. The combination of a rotary driver, a rotary driven member having aguide portion, a holder for the driver and a support for said holder,the said guide portion and support being curved about the same point inthe axis of the driven member and the support being at a greaterdistance from said point than any part of the guide portion, whereby acomplete rotation of the latter is permitted, and the driver beingmounted to rotate about an axis passing through the same point andhaving a traveler arranged and constructed to engage said guide portionand apply force thereto, the holder being adjustable upon said supportand having its portion which holds the driver extending from the supporttoward the axis of curvature of the latter at an oblique angle to theaxis of the driver.

In testimony whereof I have aflixed my signature, in presence of twowitnesses.

HORACE S. BUTTERFIELD.

Witnesses:

OLOF OTIKON, ARTHUR H. BROWN.

five cents each, by addressing the Commissioner of Patents,

Washington, D. G.

